hi,

SFB 52/53 RDREC/WRREC means read record/write record.

PN-devices or PB-slaves have different records, which are addressed by index and subindex.

The functions are described here, chapter 8.1:

System Software for S7-300/400 System and Standard Functions Volume 1 and Volume 2

 hope this helps,

regards,

hi again,

Devices are supporting different data-records. Like record with index 196 is for configuraiton of a device, and other records have other information about the device. But not only information, you can also control devices with datarecords. If you write a specific datarecord of a device, the device may act different as before. But not all devices are supporting every record.

For example there is a parameter-record for S7-1200 IO-link module:

Parameter data record

hope this helps,

regards,